A036333 - OEIS

A036333

Composite numbers n such that juxtaposition of prime factors of n has length 9.

512, 768, 1152, 1280, 1408, 1664, 1728, 1792, 1920, 2112, 2176, 2432, 2496, 2592, 2688, 2880, 2944, 3168, 3200, 3264, 3520, 3648, 3712, 3744, 3872, 3888, 3968, 4032, 4160, 4320, 4416, 4480, 4576, 4736, 4752, 4800, 4896, 4928, 5248, 5280, 5408, 5440

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OFFSET

1,1

COMMENTS

The last term is a(84018465) = 997210243 = 9973 * 99991. - Giovanni Resta, Mar 21 2013

Prime factors counted with multiplicity. - Harvey P. Dale, Jul 26 2017

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

MAPLE

isA036333 := proc(n) local d: d:=ifactors(n)[2]: return `if`(not isprime(n) and add(length(d[j][1])*d[j][2], j=1..nops(d))=9, n, NULL): end: seq(isA036333(n), n=2..5440); # Nathaniel Johnston, Jun 22 2011

MATHEMATICA

jpf9Q[n_]:=CompositeQ[n]&&Total[IntegerLength[#[[1]]]#[[2]]&/@ FactorInteger[ n]]==9; Select[ Range[6000], jpf9Q] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 26 2017 *)

CROSSREFS

Cf. A036326-A036334.

Sequence in context: A248536 A202461 A046311 * A046312 A045033 A066648

Adjacent sequences: A036330 A036331 A036332 * A036334 A036335 A036336

KEYWORD

nonn,base,fini,easy

AUTHOR

Patrick De Geest, Dec 15 1998

STATUS

approved